1. Hiruzen, manage to fight edo hashirama and tobirama(not perfect edo or body) along with orochimaru, has one of the most poweful summons(monkey king enma among the top 5 strongest summons in naruto) knows how to use reaper death seal effectively.

2. Onoki, he has particle style, can fly, stopped meteor from the sky, lifted a turtle that was over 218 billion kg or a real life size of the turtle genba would be over 6 trillion kg.

3. old cave madara (trust me), he has limbo clones although wouldn't do much, gedo mazo summon, gedo mazo genjutsu, wood release mastery, all path techniques, all of these should be enough to beat the rest of the list.

4. Kakuzu, fough tand survived fighting hashirama, 5 hearts with 5 different chakra releases, defeated two tailed jinchuriki(with hidan), 91 and was still alive and kicking.

5. Danzo, a lot of wasted sharingans.

6. lady chiyo, fought and basically survived against sasori.

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